So after a afternoon of digging through old threads I decided I'd be better off just asking here. My 06 f150 5.4 had be a little more "breathy" sounding then normal (maybe completely unrelated). Than my alternator went out, I figured great prb where that extra noise has been coming from, but no still off sounding.
Today going up a slight incline, made a whistle sound that after a few revs of the motor went away (again maybe completely unrelated). But now at idle and lower rpms it's clicking and not in sync with the engine either. Doesn't increase in speed or volume with rpms either.
My thought was sounded like ac compressor so was going to unplug the clutch to eliminate the problem hopefully. Couldn't get my fat fingers in there to do that so just turned on ac and sat and watched the clutch. That engaged and disengaged independently of my mystery click so now I'm at a lose here. Any input would be appreciated.

 

Should I be posting this in a different area of the forum?

 

your fine posting here.

It is really tough to grasp/and mentally hear what you physically hear.

If I understand correctly....the ticking noise does NOT follow with the change of RPMS?? & that it stays pretty constant regardless of what the RPMs are at?? but only really heard at low RPMS?

Can you hear a difference with vehicle moving?? or only standing still/parked?

To help rule out anything on the serpentine belt system....Slip off the belt and restart it "briefly" and see it goes away. I kinda doubt any change will be noted considering that it seems not to be RPM related. but it may cut down on other noise to help localize/identify where it is coming from.

For grins....feel the tops of the relays as it making the noise...see if one or two are warm to the touch...replace those relays & see if it goes away.

the whistle sound hints of a vacuum leak somewhere.

Otherwise...you may need to post a video of the noise ...or get a mechanics stethoscope to zero in on where this is coming from.

 

Doesn't matter if it's in drive or park, moving or not. Did notice it does it more often (every few seconds or so) when the truck has warmed up. I'll get it in the garage again tomorrow check for warm relays, gonna have to do a little research to locate em.

 

And yeah you nailed it on the description of frequency. Is more or less random but doesn't get louder or faster with rpms .. I'm really bummed it wasn't the compressor. After some earlier reading had heard low refrigerant can cause the compressor to kick in and out, even in the winter. Thought for sure I had a cheap problem now not so sure

 

hoping this helps get to the root of the problem

 

Does it go away if you shut off your Heat and A/C??

 

No it does not. I did notice that I can feel the click with my finger on the belt tensioner. Tomorrow I'll pull the belt and look into getting a new tensioner.

 

Have you done this yet?

If it goes away, shut it down, and before putting the belt back on, spin all the driven pulleys and see if any of them feel rough.

 

Found a bad tensioner pulley bearing. New pulley and clicking gone.

 

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congrats!